Former White House chief of staff Rahm Emanuel has launched a scathing attack on Citizens United, the ruling that opened the floodgates to unlimited political spending by a handful of billionaire donors, calling it one of the "worst decisions of any supreme court in American history".

The mayor of Chicago has added his voice to a growing chorus of criticism for the judgment that removed long-standing restrictions on corporate spending on political campaigns.

Emanuel, who was Barack Obama's chief of staff at the time Citizens United came down, said the ruling had damaged the court's reputation as the nation's "high court". He told the Guardian: "I think the decision on the super Pacs will go down as probably in the top five single worst decisions of any supreme court in American history."

"What Sheldon Adelson is doing, the supreme court with all their wisdom and foresight thinks is legal," Emanuel said. "Money coming from China – now you tell me how the supreme court earns itself the word 'High court'."

Together with the subsequent ruling, SpeechNow, the Citizens United decision paved the way for the proliferation of super Pacs, the largely Republican groups that are distorting this year's presidential election through a vast injection of private cash.

Super Pacs have become the defining feature of the 2012 election cycle. Collectively, they promise to raise several hundreds of millions of dollars between now and the presidential election on 6 November – much of which is being spent on anti-Obama negative attack ads. Some analysts expect the total raised by the groups to exceed $1bn.

It is possible that the supreme court could agree to look again at its decision in the wake of a case in Montana where the lower courts have openly defied the ruling. The decision of the supreme court over whether or not to reconsider Citizens United could come as early as Monday.

Last month the retired supreme court justice John Paul Stevens, one of the four dissenting justices who opposed Citizens United, said that in his view a revision of the law was now inevitable. The original judgment was made after the justices split five against four, with the court's five conservative members being in the majority.

Emanuel made a comparison between billionaire funders of super Pacs and John Edwards, the former senator who was unsuccessfully prosecuted for misusing campaign funds to cover up a secret affair during the 2008 Democratic primaries. "Think about this: the supreme court and the justice department are all part of one legal structure – we are a country of laws," Emanuel said.

Adelson is the most prominent of a new breed of super-wealthy political donors who have used Citizens United to pour huge sums into Republican-supporting super Pac.

Adelson is just one of a rash of wealthy Americans who have seized the opportunity afforded by Citizens United to intervene in the presidential race. An analysis by Forbes found that Restore Our Future, the super Pac backing the presumptive Republican candidate Mitt Romney, is being funded by no fewer than 32 billionaires .

By contrast, Obama's re-election campaign is being backed by relatively few wealthy individuals this year, led by Jeffrey Katzenberg of the Dreamworks animation company.

Emanuel's strong antagonism towards Citizens United was shared by his former boss. A week after the court made its decision, Obama said in his 2010 State of the Union address, delivered under the noses of the nine justices, that "I don't think American elections should be bankrolled by America's most powerful interests, or worse, by foreign entities."